1PQE - jobs hard to find. If you want to leave so early means you really die die dunwan stay in law, and essentially don't know much, people still need to train you. Nobody really wants 1PQE.

3PQE - just about enough experience for people to start considering you, but if you want abit longer, your pay after SA range is alot higher, so jumping out now might be financially less worth it.

5PQE - Pay is high enough that you can go into in-house, PQE also very high for in-house. But at this stage, slog 1-2 more years can make partner liao, why not just slog it out.

Essentially, all levels going to have their own push/pull factors. Just leave once you find a good enough job that pays relatively well lol.